1. Field of the Invention
The present invention relates to an aircraft seat pan assembly structured to be mounted on an aircraft seat foundation, the seat pan assembly being structured to provide for a minimal stroking distance between the seat pan and any underlying seat frame portion while still appropriately withstanding a maximum downward spine load as determined by Federal Aviation Association (FAA) guidelines.
2. Description of the Related Art
In an aircraft seat frame, and particularly in an aircraft seat foundation, the seat pan is the portion of the seat foundation which spans the supports of the seat foundation and actually supports the weight of a seated individual. Most conventionally implemented seat pan designs incorporate nylon or other material panels or meshes which are secured along all sides thereof to the cross supports and side rails of the seat foundation. Further, in addition to supporting an individual sitting on the seat foundation, the seat pan also functions to conceal a variety of underlying seat frame portions, such as recline mechanisms, swivel mechanisms, and various other articles associated with the aircraft seat and aircraft seat frame, thereunder.
The distance between the seat pan and the underlying seat portions concealed thereunder is generally called the stroking distance. Under normal loads, and under test loads, however, the seat pan will tend to sag downwardly, thereby reducing the stroking distance. During FAA testing procedures, which have been modified to include more stringent testing requirements and are now having a practical impact on the related industry, a downward spine load of a predetermined intensity is exerted on the seat pan. The primary criterion utilized in order to determine whether the seat pan assembly passes the downward spine load test relate to the seat pan remaining securely attached to the seat foundation and to the seat pan not sagging so far as to contact or come too near to the underlying portions of the aircraft seat. With regard to maintaining the seat pan securely fastened to the seat foundation, this is conventionally achieved through secure bolts and by the strength of the material construction of the seat pan. Unfortunately, however, because of the need to maintain maximum lightweight construction, and because of the flexing that is generally necessary in the seat pan for a comfortable seat assembly, the initial stroking distance of the seat pan must generally be quite large due to the amount of sagging which the seat pan will undertake upon the intense downward spine load. As such, there is a substantial amount of wasted space between the seat pan and the underlying portions.
As previously stated, the more stringent regulations and testing requirements enacted by the FAA are now impacting the aircraft seat manufacturing industry. Presently in the related art, others have adapted to the new guidelines and have achieved acceptable stroking distances that do not allow contact by the seat pan, under a load, with the underlying seat portions, merely by increasing the initial stroking distance to permit an increased sag. Such procedures, however, are inefficient and do not seek to provide a real solution to a primary problem sought to be addressed by the test criteria, namely the prevention of component failure as a result of the excess sag. Moreover, the present approaches only provide a coarse, jerry-rigged remedy that can lead to other problems such as the need to add material, and therefore weight, the need to elevate the seat foundation to un-practical levels, or the need to cut out or lower some underlying seat portions such as swivel or slider mechanisms. Accordingly, there is still a substantial need in this specialized and related art to provide for an improved aircraft seat pan assembly which provides for a minimal initial stroking distance, yet is capable of withstanding the downward spine load associated with FAA testing guidelines.